Let l be the slant height of the frustum. We have r = 8 cm,
R = 20 cm and h = 16 cm
Now, volume of the container
Volume of container = 10449.92 cm3
Volume of container =
Volume of container = 10.44992 litres
= 10.45 litres (Approx)
∴ Cost of milk at the rate of Rs. 15 per litre = Rs.
(10.45 x 15) = Rs. 156.75
Now, Total surface area of the frustum = π (R + r) l + r2
= {3.14 (20 + 8) x 20 + 3.14 x 82} cm2
= 3.14 x (560 + 64) cm3
= (3.14 x 624) cm3 = 1959.36 cm2
Cost of metal used = Rs.
= Rs. 97.96 (Approx)
A bucket made up of a metal sheet is in the form of a frustum of a cone of height 16 cm with diameters of its lower and upper ends as 16 cm and 40 cm respectively. Find the volume of the bucket. Also find the cost of the bucket if the cost of metal sheet used is Rs. 20 per 100 cm2. (Use = 3.14)
A cylindrical vessel, with internal diameter 10 cm and height 10.5 cm is full of water. A solid cone of base diameter 7 cm and height 6 cm is completely immersed in water. Find the volume of
(i) Water displaced out of the cylinderical vessel,
(ii) Water left in the cylindrical vessel.